(1) Field of the Invention
This invention relates to a microtiter plate suitable for use, for example, in reacting liquid portions each of which is of a minute quantity.
(2) Description of the Prior Art
It is now known to conduct the detection or measurement of a component contained in a liquid sample or reagent of a minute quantity by placing the liquid sample or reagent in a well of a microtiter plate, inducing a chemical reaction, biological reaction or the like, which is accompanied by color development or discoloration, in the liquid sample or reagent and then determining results of the reaction by optical means, namely, by projecting a beam of light onto the resultant reaction mixture in the well and measuring the intensity of light transmitted therethrough. Since this method requires the sample or reagent only in a minute quantity (usually, less than 1 cc), it is applied widely for the inspection of water quality, the diagnoses of diseases based on blood samples and other purposes.
In a method of the above-mentioned sort, it is generally required to divide each sample into many portions and then to react the resulting sample portions with many reagents of different kinds respectively so that the same sample can be tested with respect to many items. As an alternative, it is also required to react many samples with the same reagent so that the same test can be performed on such many samples. In order to carry out such reactions efficiently, microtiter plates such as that shown in FIG. 3 have conventionally been used. In FIG. 3, a microtiter plate 20 is made of a transparent material and defines a number of round-bottomed reaction wells 10 equipped with openings 11. Each of the reaction wells 10 may be adapted as a reaction vessel. A liquid sample or reagent is dropped from an automatic buret into each reaction well 10. After completion of a prescribed reaction or treatment, results of the reaction or treatment are detected by optical means.
The procedures for the reaction of a liquid of a minute quantity and the subsequent detection of results of the reaction, which make use of such a microtiter plate as described above, are however accompanied by a variety of serious problems as a matter of fact. For example, a beam of light the spot diameter of which is about 2 mm is usually employed in the procedure for the detection of results of the reaction. However, detection results obtained vary significantly and do not have sufficiently high reliability. For these reasons, information obtained by such a method as described above has a low value only. Its merit cannot therefore be utilized fully although the method itself is excellent.